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Friday, 25 March 2016

New Zealand's receding glaciers

The
precipitous collapse of the NZ glacial index continues apace in a non
linear fashion.

The idiots who think that NZ can step back from hydro
carbon energy production to so called renewables need a wake up call,
here it is.

"Many New Zealand glaciers are important for
hydropower: Lake Tekapo and Lake Pukaki are both utilized for
hydropower. Hooker Glacier, Mueller, Murchison and Tasman Glacier
drain into Lake Pukaki, where water level has been raised 9 m for
hydropower purposes.

Water from Lake Pukaki is sent through a canal
into the Lake Ohau watershed and then through six hydropower plants
of the Waitaki hydro scheme: Ohau A, B and C. Benmore, Aviemore and
Waitaki with a combined output of 1340 MW. Meridian owns and operates
all six hydro stations located from Lake Pūkaki to Waitaki. The
reduction of glacier area in the region will reduce summer runoff
into Lake Pukaki and this hydropower system."

There
is not one political party in NZ facing up to the reality of our
dependence on fossil fuels as these sources of energy are in their
terminal phase.

John
Key and his climate change denier Minister of Climate Change Tim
Grosser who was coincidentally also the Trade Minister driving the
TPPA came back from ‪#‎Copout21‬ in Paris rubbing their hands
in glee that there were no bonding emissions targets.

We
have all been chucked under the abrupt climate change bus, brace for
imminent, non-linear impact.

And
my own comments

Not
only that but when the snow on the Southern Alps goes so too do
Canterbury's large snow-fed rivers, We have a
California-in-the-making

Red
arrows are the 1990 terminus and yellow arrows the 2015 terminus
locations.

Overview

The
Southern Alps of New Zealand are host to over 3000 glaciers that owe
their existence to high amounts of precipitation ranging from 3 to 10
m (Chinn, 1999). The list below examines the changes of 12 glaciers
examined in a separate post. The NIWA glacier monitoring
program has noted that volume of ice in New Zealand’s Southern
Alps has decreased by 36% with the loss of 19.0 km3 of
glacier ice, from 53.3 km3 in
1978 to 34.3 km3 in
2014 (New
Zealand Govt., 2015).
Volume loss in New Zealand glaciers is dominated by 12
large glaciers (Salinger
and Willsman, 2008).
More than 90% of this loss is from 12 of the largest glaciers in
response to rising temperatures over the 20th century (Chinn,
1999).
In the 1972 map of the region there is no lake at the terminus
of the Tasman Glacier, Mueller Glacier or Hooker Glacier; each are
substantial in size by 2015. Each lake continues to expand and as
glacier retreat continues .From 1977-2015 NIWA has conducted an
annual snowline survey, in six of the last nine years the snowline
has been significantly above average and three years approximately at
the average (Willisman
et al., 2015).
This has driven the widespread glacier retreat underway. In each case
the retreat of the largest glaciers has been enhanced by the
formation and expansion of lakes, in this newly developing lake
district. Dykes
et al., (2011) identify
the role of glacier lakes in accelerating the retreat of Tasman
Glacier. The retreat of these glaciers has until recently been
slowed by debris cover and the long low slope ablation zone segments
(Chinn,
1999).
Glaciers that lack debris cover and have a steeper slope have a more
rapid response time, such as Fox Glacier and Franz Josef Glacier
(Purdie
et al., 2014).
These two glaciers have been in the news of late due to rapid
retreat causing glacier
tours of the
lower reaches of the glacier unsafe. NIWA reported
that February
of 2016 was
the second warmest month of any month in New Zealand, which will
drive snowlines higher and enhance glacier melt this year.

Many
New Zealand glaciers are important for hydropower: Lake Tekapo and
Lake Pukaki are both utilized for hydropower. Hooker Glacier,
Mueller, Murchison and Tasman Glacier drain into Lake Pukaki, where
water level has been raised 9 m for hydropower purposes. Water from
Lake Pukaki is sent through a canal into the Lake Ohau watershed and
then through six hydropower plants of the Waitaki hydro scheme:
Ohau A, B and C. Benmore, Aviemore and Waitaki with a combined output
of 1340 MW. Meridian owns and operates all six hydro
stations located from Lake Pūkaki to Waitaki. The reduction of
glacier area in the region will reduce summer runoff into Lake Pukaki
and this hydropower system.

Gunn
Glacier in, 2006 above and 2012 below,Google Earth image. Red
arrows the 2006 terminus position yellow arrows 2012 terminus
location. The glacier lost 25% of its area in six years.